Electrical system



BEST AVAILABLE COP.

Nov. 11 1924.

L. H. MILLER ELECTRICAL SYSTEM an ina Filed Aug. 19, 1916 Patented Nov.11, 1924.

UNITEDTSTATE'S BEST AVAILABLE COP.

PATENT .OFJFICE j Lrnns Y H. MULL or cnroAGoiriltritois.

I ELECTRICAL sewn Application filed August 19, 1916, Serial No;532,859f'Renewe d January 30, 1922.

To all whom it may c0'n0em:

Be it known that I, LINDSAY H. MILLER, a citizen of the United States,and residing at Chicago, in the county of Cook and State of Illinois,have invented a new and Improved Electrical System, of which thefollowing specification is a full disclosure.

This invention relates to an electrical system, and with regardtocertain more spe;

eific features, to a powerplant embodying an internal combustionIengine, .afdynamo connected; therewith, jv'o'rlz circuit and fastoragebattery. This invention an 'im' provement on the inv'ention'setforth inthe application'of Harvey S. Pardee for patent on electricalsystem, Serial Number 92, 3}; filedApril20,19 16."

One of the objects of the present invention is to provide electricalsystem constructed of parts easily obtained on the market, readilyassembled, and capable of operation for an extendedperiod'without'expert ate g. 1 ,i ,.;i I Another ob'e'ct isjtlie provision ofsimple, d ra and e en fappilat gmf.fie e hi ing current to agworl ifcircuit by, means ofa generator driven by an iiiternalcombustion engineor other engine:v inherently incapable of'startingitseljf. Anotherobject is the provision of a sys tem of the above type infwhich a smallstorage battery may be effectively employed, in place of the largebattery now commonly in use, the present system aflfordingauto maticoperation, accuracy of regulation, and protection to the battery.Another object is'the rovision of an ef ficiient and inexpenis'vecarginq system for a st orage battery, so designed t at the generator maysupply the lamps and charge the battery simultaneously withoutsubjecting the lamps or other translating devices, to a voltage higherthan the normal dischargevoltage of the battery.

Another object is the provision of improved apparatus of the above. typein which notice is automatically given to the operator in casehis'atte'ntion is needed at any time, and this prior to anydisconnection of the lamps from their source of current.

Another object is the provision of reliable and efficient means forcontrolling the analysis of'thi'slinventionl fi This invention"accordingly consists-in the features *of 'construct1on, -combin'altionof parts, and in-the 'uni'que' relations of the members and in therelative proportioning and dispositions thereof; all asmore completelyoutlined herei-n. Toenable others skilledin the art-so fully tocomprehend the underlyin features thereof'thatthey may embody t esame''by the numerous modifications in structure and relation contemplated by".this invention, drawings depictingdiagrammatically a preferred te mhave been annexed gas Ya 1 part of this disclosure and"'in'saiididrawings;

"Ifi'g'ure l'gisa diagnamm'atic representation of an electrical" systemincorporating certain features of-th'e present invention; and "Figure 2illustrates 'a'modification, relating primarily toasimplifi'cationof there- In considering the relation of this invention"to the priorlart; it'may be noted that for many years there has been 'a demand foranelectrical system in' which a work circuit,'for lamps, motors; or 'other translating devices, couldbesupplied with current fromfla dynamodriven by an internal-com-v bustion engine; with provision forfurnishing a small amount or current as for nightlights, withoutrequiringthe operation of the engine and generator at such times; afurtherfrequirement has beenthat the en tire system should besufficiently automatic that no frequent or expertattention is needed,durable so that no expert inspection or repair would be required forlong periods of time, and inexpensive both as regards first costs andoperating costs, so

1 equal to the discharge voltage of the battery that the system iscommercially applicable to small, isolated installations. In many, ifnot all of the present-day apparatus designed ,for. isolated powerplants, the first cost and depreciation of the stor ag'epbatteiy is alarge factor in the total GXPBIISQiiiCldent to the purchase andmaintenance of the plant. As the descriptionof the present inventionproceeds, it will be seen that these rigid requirements have beenmet,'1n an apparatus which is at. once inexpensive, autoinatic,efiicient and reliable.

Briefly, the present invention utilizes a combined generator andbattery-charging booster which supplies a: voltage to the line and anexcess charging voltage to the battery greater-than the voltage suppliedto the line, whenever the generator. is running normallyg Whenthe-generatoris not running, the booster armature winding of thecombined; generator remains :jntthe battery circuit but generates n9gvoltagebecause it is; at. restl There is; preferably provided anampere-hour meterwith certain gCODtEIOtS and.

electrical connectionseto a .main SWlt0h=WhlCl1 operate thatswitchand-automatically start up-jzthe plant; and shut it down at the-propertiinesn depending upon the state of-charge of the battery.Themaingswitch is arranged 3 also to close automaticallyfand start upthe plant whenever thelamp load draws a current" excesslof-thecapacitypf the-bat tery, which: in this casemay relatively 's'malln aThemain switchautomatically opens when: the lamp load 1 drops, down 5 1610? the capacity; of the Z- andthe battery has; reaehecla. -.state near-fnllf charge ions auxiliary; devices maybe added to protect) theapparatus, give; an; alarm and to I cut- .off the engine-startingcircuit .when the,

: stant of starting the engine,

This fluctuation of the lamp voltage and candle-power has the advantageof giving a distinct Warning to the operator whenever the engine isstarted.

- Referringnow to the accompanying drawings, there is illustrated at I aportion of the intake of an internal-combustion engine E: :1 butterflyor other valve V is located in the intake I and is adapted to beoperated by means hereinafter described, so as to increase the fuelsupply to the engine at certain times and to move in the oppositedirection to decrease the fuel supply at other times." Mechanicallyconnected to the engine E is a dyiiamo electric machine D,

which is utilized as a motor to start the engine and when the engine 15running IS utilized as a generator to furnish current to thestorage-battery B and to the work circuit IV.

An integrating meter 1, preferably an ainpere-hour meter as hereillustrated, has a contact-making pointer or other indicator 2 whichindicates the state of charge of the battery B and, in addition, effectscertain circuit-changing operations hereinafter described. Avalve-operating regulator 4, a main switch 6, a relay 7, a dynamotripswitch.9 and a battery trip-switch 10, may also be provided. Thestructural ments and their assembly perhaps caii'be best described inconnection with an explanation of the various operationsand circuitchanges that occur in the several'phasesor events details of the variouseleof the cycle of'operations, of the; system.

Assume, therefore,- that the engine and :dy name are at rest, thatno-cu'rrent ,isfio iv'in'g in the work circuit and that-thefbatteryfisinza stateof partial chargesuch that the indicator 2 of the meter 1stands at point 12.

Atthis time the switches 9' and IO'are closed; the contacts &6 areclosed, the'inain switch 6 is open (down), the regulator 4 is in itsopen-throttle position (solenoid 13 down) in- Figure 1, with l theleft-hand movable contactor l4tfth81'0f contactingwith its lefthandcontactor 15, and the right-hand mov able 'contactor 17 of the relay isseparated and the relay 7 is in the position indicated from itscontactor 18. If now a lamp load w of less than, fOreXampIe, one ampere,be turned on in the work circuitiv, then current will flow fromthepositive side of the battery B, through the lead 19, battery tripswitch10, lead 20, coil. 21 of the meter l.

lead 22, lamp-current coil 24 of the main switch 6 and lead 39 thencethrough any lamps L, L, that are turned on, thence tothe ground, fromground to'the grounded terminal 25 common to the two armature windings Hof the dynamo D, through the low-voltage armature winding 26, negativebrush 27 thereof, and lead 28, to the negative pole of the battery. Theflow through the armature winding 26 encounters none but ohmicresistance, since the dynamo is at rest and the field excitation dead.This lamp load causes aslow discharge of the battery and consequently aslow clockwise movement of the indicator 2, which moves toward thestart-charge contact 30.

\Vhon the indicator 2 reaches the contact 30, a circuit is closed fromthe positive side BEST AVAILABLE cos.

ing-block 36a quarter-turn, .through the ratchet 37. This rotation ofthe spacingblock 36 breaks the relay circuit at the contactors 14. 15,de-energizing the relay winding 33 and allowing the plunger 34 to bewithdrawn upward by its spring into position for another throw. At thesame time the contacts 14.- and 17-18 are closed. The coutactors 1718close a circuit from the positive side of the batterytthrough elements19, 10, 20, 21,- lead 40, right-hand movable contact- 17, contact-18,lead 41, voltage coili43 of the main-switch 6,- ground, elements 25, 26,27 and 28 to the negative side of the battery.";This energizes thevoltage coil-{13 of the main switch, which thereupon pulls upwardly 'itssolenoid-core 44, with sufficient forceto close the contactsfi.

At about the same time,-the're1ay-R is 'sufiiciently energizedtoseparate the contacts 46 to remove-a'short-circuit around the en ginemagneto 4:7, or,depending' upon the style of ignition used for theengine-the circuits might be altered so that the opera.- tion of therelay'R would close the ignition circuit; in -either case, the contacts46 are intended to render the engine ignition operative when the-relay Ris sufiiciently energized and inoperative at other'times.

The effect of closing the main contacts 45' is to close-amircuit fromthe positive side of the batter through'elements'lt), 10, 20, 21, 22,45, dynamo current coil 48 of the main switch 6, coil of:-relay-' R,lead 49, dynamo trip-switch 9, lead 50, current coil '52 of theregulator 4, series field 54 of the dynamo D, positive brush 55,high-voltage armature winding -56,- intermediate or grounded terminal25, low-voltage-winding 26, brush 27 and lead 28 to the negative sideofthe'battery. r

Simultaneously the shunt-field winding 58 and the voltage coil 59- ofthe regulator t','connectedin series, are energized; these coils are,for the moment, energized but slightly, however, owing to the heavyohmic drop in the battery. A strong current flows through the circuitincluding the armatures and series field of the dynamo, causing thedynamo to rotate substantially as a series motor, with a largestarting-torque, the series field 54- at this time predominating overthe shunt field 58; this rotation of the dynamo rotatesthe engine Ethrough the mechanical connections between them, and

this serves to start the engine. ;The. current through the current coil48 ofthe main switch at this time tends to assist in closing thecontacts 45 thereof more tightly, thus securing a firm and positivecontact.

After the engine has started to rotate under its own power, the counterelectromotive-force generated in the armature windings 26, 56, raisesthe voltage acrosstlie terminals of the dynamo, thereby increasing thepower of the coil 59 and shunt field 58 and reducing the power in theseries field 54L, until the dynamo voltage equals and then exceeds thebattery voltage. Then the series field reverses, and thereafter, duringthe operation of the dynamo as a generator, the series field. opposesthe effect of the shunt field. The series field is preferably strongenough relatively to the shunt field to afford a marked drooping of thedynamo-voltage characteristic.

Now that the engine is running under its own power, current is deliveredfrom, the positive lead of the dynamo through theele; ments;52, 50, 9,49, R, 4:8, 4:5, and thence in two. branches. The first branchincludesthe lamp current coil 2%, main 39, lamps L, L, ground, andgroundedlterminal 26 ofthe dynamo, giving at the lamps a voltage equalto the voltage across the high-voltageovinding 56 of the dynamoyinpracticeithis is preferably 110 volts, although obviously any othersuitable standard. ofvoltage may be used. The second branch includes theelements 22, 21, 20, 10, 19, thence through the battery to charge thesame, thence through low-voltage or booster winding26 offthe dynamo, tothe grounded terminal 25 of the dynamo; so that the voltage across thebatteryis at this time equal to the sum of the voltages across the twowindings 56, 26, of

the dynamo. The high-voltage winding carries preferably apressure ofllOvolts, and

by proportioning the low-voltage,winding for, say, approximately letvolts, the battery on charge receives 124 volts at its terminals,

which is a suitable charging voltage for a lead battery whose dischargevoltage is 110;

however, these proportions may naturally be varied to meet therequirements of the particular battery to be used.

The dynamo voltage is maintained constant by suitable means such as theregulator 4., whose. solenoid 61 is pulled u wardly in case of atendency to excessive v0 tag-e across the coil 59, to move the valve Vtoward its closed position, thereby reducing. the fuel supply and speedof the engine and consequently restoring the dynamo voltageto its normalvalue. or tendency to reduction of the voltage causes a lessened powerof the coil 59.5Which allows the solenoid core 13 to drop slightly,thereby opening the valve. admitting niore fuel, speeding up the engineQJICLI'LYDMDO, 7

Similarly a slight reduction BEST AVAILABLE COP.

and restoring the voltage to normal. By means of this regulator, then,the dynamo voltage characteristic is determined so that despite changesin load, or the condition of the battery or other variables such astemperature and quality of fuel, the voltage on the load is notaffected. It is possible by means of the compound winding on theregulator to give a rising characteristic to the dynamo voltage in orderto compensate for voltage drop in the line leading to the lamp load. Thecompounding is effected by the current coil 52, which carries the outputcurrent of the dynamo and during normal operation opposes magneticallythe potential winding 59. By properly proportioning the ratio ofampere-turns on the current and the potential windings 52, 59, it ispossible to give a flat, a rising, or a falling characteristic to thevoltage across the work circuit. This regulator compensates for theinherent drooping characteristic of the dynamo as well as for allother-conditions. It is preferably equipped with a dashpot or othersuitable damping means 61 to' prevent'hunting' or over-regulation duringordin'ary load fluctuations and sudden closing of the valve due to thestrong action of the current coil at the instant of starting the engine.

As the'charg'ing of the battery progresses, the meter indicator 2moves-counterclockwise. When the indicator reaches the stopchargecontact 63, a circuit is closed from the positive main 490i the dynamocircuit, through elements 22, 2, 63, 64, contactors and 14 (closed aspreviously explained), coil 33 of relay 7,- to ground. This energizesthe relay coil 33, which thereupon pulls downwardly its solenoid core34, imparting a quartenturn through the ratchet 37, to thediamond-shaped spacing-block 36. This rotation of the spacing-block 36breaks the circuit at the contactors 65, 14, andopens the circuit at theright-hand contacts 17, 18. The break at 65, 14', opens the circuitthrough which the relay had been previously energized, thus allowing theplunger 34 to be withdrawn by the spring 35 into position for anotherthrow. The separating of the contactors 17, 18, opens the circuitthrough the voltage coil 43 of the main switch 6, and causes the switchto open its contacts 45, assuming still that the lamp load is one ampereor less. The opening ofthe mainswitch contacts 45 disconnects the dynamofrom the battery and work circuit and deenergizes the coil of theunderload relay R, which thereupon closes its contacts 46, deenergizingthe engine ignition and causing the engine to stop. The conditionsprevious'ly assumed are now restored. namely, the engine and dynamo areat rest, and bat tery is on slowdischarge and supplies the one ampereorless that is required for the work circuit. As the battery slowly,discharges, t-he meter pointer 2 reaches again the start-charge contact30, and the cycle above described is repeated.

An object of the relay 7 is to relieve the contacts on the meter 1 ofthe duty of carrying the current and breaking the inductive currentthrough the voltage coil 43 of the main switch.

If at any time the current inthe work circuit rises above, say, oneampere when the dynamo is not running, the starting of the dynamo iscii'ected at once, without waiting for the battery to discharge to thestate indicated by the start-charge contact 30 on the meter. Thisimmediate starting of the engine is eii'ected through the lamp-currentcoil 24 on the main switch; this coil, when energized with more than,say, one ampere of current, raises the core 44 of the main switch 6,after which the starting of the dynamo is effected as in the precedinginstance, where the coil 44 was raised by means of the voltage coil 43.vIf now the battery be comes sufficiently charged to cause the indicator2 to reach the stop-charge contact 63, the relay 7 will not be affected,as it is inits Figure 1 position. The voltage coil 43 of the main switchis de-energized at this time, but

the core 44 thereof does not drop, because i i there is more than oneampere of current in the lamp-current coil 24, and this coil is thusenergized sufficiently to keep the main switch closed even though thevoltage coil 43- is de-energized'. Nor does the underload relay R-operate to close the ignition contacts 46, because the current flowingthroughthe coil of this relay is sufficient to keep the relay energizedand the contacts 46 separated. The charging of the battery thereforecontinues, but at a decreasing rate, becausethe counterelectromotive-force of the battery is increasing, and the impressedvoltage (from the dynamo) is constant. As the charging progresses, themeter indicator rotates further' counter-clockwise, until it reaches thestop 67, indicating full charge, or it preferred, an overcharge. Furthermovement of the meter indicator is prevented by this stop; this does noharm to the meter, and

serves to indicate that the battery is fully charged, and also tends toinsure that the indicator of the meter is in harmony with the conditionof the battery. Then, when the lamp current falls below one ampere, thelamp-current coil 24- permits the-core 44 to drop, thereby opening themain switch, disconnecting the dynamo from the battery and lamps, andopen-circuit'ing the underload relay R, which thereupon closes itscontacts 46, de-ene'rgiz'ing the engine ignition and stopping theengine. The reason for preferably separating the stop-charge contact 63and full charge stop 67 by an interval determined by the constants ofthe-system, is

that the charging current tapers ofl. markedly toward the end of thecharge and considerable time is required for the indicator to move overthis part of its travel' If the stopcharge contact 63 were t a pointrepresenting full charge, and the lamp load below one ampere, the enginewould be kept running a long time with an insignificant current andconsequently low efficiency. It is preferable to place this stop-chargecontact 63 at a point representing about eighty to ninety per cent offull charge and to depend upon the exigencies of load conditions to runthe engine long enough to efi'ect a complete charge and. occasionally adesirable overcharge of the battery; this will bring the indicator 2 ,upagainst ,the stop 67 and when the battery next goes on discharge themeter will be still instep with it. It will thus. be seen tha-t theengine is started at any time when thelamp current exceeds one ampere,and remains in operation as long as the lamp current remainsabovethatvalue, and supplies current to the lamps and to the battery, and thatwith the lamp current less than one ampere, the engine is startedautomatically, when the battery becomes sulficiently discharged, and isautomatically stopped ,whentthe charging has progressed to apredetermined extent. It will be clear, moreover, that when the dynamois at rest the lamps are supplied from the, battery through a circuitincluding the low-voltage winding of the dynamo, which, however, offersat this time only an ohmic resistance to the passage of the currenttherethrough, since thearmature is not rotating and the field is notenergized; on the other hand, when thedynamo is in operation, thebattery is charged at a constant voltage equal to the sum of thevoltages across both of the dynamo armature windings, while the lampsare supplied fromthe high-voltage winding only, and at a constantvoltage equal to the discharge voltage of the battery. In this way, thelamps receive practically the same voltage whether the battery is oncharge or discharge, the battery receives on charge a constant impressedvoltage in excess of its discharge voltage, and the ratio of charge todischarge voltages may be predetermined to meet the characteristics ofthe battery by properly proportioning the relative voltages of the twoarmature windings 'cf the dynamo. Again, the regulator provided for thepurpose of maintaining a definite voltage characteristic operatesdirectly upon the fuel supply to the engine, thus avoiding the lossesand complication incident to other types of regulation; and by suitabledesign of this regulatorin combination with the drooping characteristicof the dynamo, the engine is caused to run at a higher speed at fullload than at light load, thereby efiecting an engine operation conduciveto fuel economy, since at light load, when less fuel needs to be takeninto the engine, a lower speed is advisable in order to reduce theamount of throttling needed, and to maintain a more nearly constant andeconomical mixture of fuel and air throughout 9,- ground, and elements25, 26,27 and28,

to the negative side of the battery. Thisjen; ergizes the coil 73 which,opens the tripswitch 9, thereby disconnecting the dynamo from thebattery and lamps, and protectin the battery from further;dischargevthroug the dynamo. Atvthe same time, an alarm circuit may beclosedeitherby theclosing of the circuit at 2, 71,,or by the movement of thetrip-switch 9.to its open-circuit positi0n;-the latter device isillustrated, conventionally as comprising the bell 75, thefcontacts 76adapted to be closed when theswitch 9. is open and connections tobattery and to ground; this bell would naturally be located withinhearing distance of the operator, and

would continue to ring, using a negligible amount of currentfrom thebattery, until the operator responds to the warning. An

additional warning, inherent in the apparatus consists in the decreasingvoltage and candle-power of the lamps as the rapid discharge of thebattery causes its voltage to drop to a marked extent. It will be notedthat this opening of the dynamo trip-switch 9 does not disconnect thelamps from the battery, so that the operatorhas the use of i thelighting circuit for locating the trouble, and the work circuit isavailable for illumination and other purposes. If the battery dischargesstill furtherbefore the trouble is removed, the battery may be preventedfrom being permanently damaged, by another safety device, comprising thebattery-trip contact 7 8, which is engaged by the meter indicator 2 whenthe latterhasmoved clockwise far enough to indicate a nearly-dischargedcondition of the battery. When the indicator reaches this contactj78,--a circuit is closed from the positive side of the battery, throughelements 19, 10, 20, 2, contact 78, lead 79, coil 80 of batterytrip-'switchlO, ground, and elements 25, 26, 27 and 28, to the negativeside of the battery. This energizes the coil 80, which opens the batterytrip-switch 10, thereby disconnecting 'the the r s eg te; b

BEST AVAlLABLE COP".

battery from the lamps and preventing any further discharge of thebattery, except possibly the small current needed for the alarm circuit75, 76 and for a trouble lamp 7'. if these circuits are connected to thebattery side of the switch 10. Contact 78 also Serves as a mechanicalstop to the meter movement 7 As an emergency device the hand-controlledswitch 91 is rovided, which in connection with the lcac s and 92 isarranged to short-circuit the main switch 6 and eliminate itsuse inconnection with the system whenever it becomes inoperative for anyreason or is removed for repairs. By the use of this emergency switch91, it is possible to continue the operation of the systemnonautomatically whenever trouble develops in the control mechanism.aprotective device to prevent the wide opening oftlie throttle Vwhenever the coil 59 of its connections should open-circuit for anyreason, tending to cause the engine to run away, there is provided asystem of contactsand connections 98. which render the en ine ignitioninoperative when the switch is e-energized, thus operating in a mannersimilar to theoperation of the underload relay R and its contact-s46.

, It is to benoted that-thecompounding of ulator 4, depends to a certainextent upon the'resistance of the battery. Thus, if

battery-were large with practically zero resistance, the voltagecharacteristic of the preferably be somewhat drooping, since the dynamounit D operates in parallel with the battery unit B and electricalflmitsin parallel will ordinarily. not diyide the load to the best advantageif their veltage characteristics are flat or rising. Howeyer, since inthis case the resistance of the battery is of considerable magnitude,its

characteristic is markedly drooping and the character st c of theregulator may be made -.flat or somewhat rising and still not act tocause the unit-D to assume an excessive load in charging the battery inaddition to the load of they work circuit. It is understood that thecurrent winding 52 of the regulator 4 may either aid or oppose thewinding 59. the proportibning and relations of, these windings dependingupon the constants of the system. In respect to parallel operation,

thev division of L ad between the units l) and 4 B is somewhat analogousto the parallel operationof units DD and D. p

Furthermore, means are provided for preventing excessive speed of theengine due to accidental dropping of the load while the enginethrottleis openwithout requiring the use of a speed limiting overnor on theengine. This means is found the underload relay R, which becomesde-cnergized if an open circuit occurs in the gene'rator or generatormains, and renders the Cally protecte dffr'om over=speedi req mu the useof a speed, limiting engine ignitioninefiec'tive, "thereby stopping theengine. lVitho'utsuch means, an'o'pe'n circuit, as for example, betweenthe: brush and commutator 56, wouldcause the'dy name to drop itsloadpand the"- ar1i1ature windingZG-wuld then niotorize fr'oiirtliebattery through a circuit 10, 20, 21, 22,241, 39 1, Ii, gimme-25, 26, 27and 28;'-th're suiting heavy ohmic drop in the battery would weaken theregulator' coil 59, which wcaild tend to open the eng ne'throttle, andthere would he danger of the engine running away unless a speed limitingdevice were provided. The underload relay R; however, automaticallystops the engine in an en'icrgcncy suchas this, andithe neccssity for aspeed limit device to protect the engine from this danger isobviated.Means if the shunt field"is opeii circuited, the :regulator coil 59willbe' cpmpletely de' ene'rgized, so that the plungeul'will'elos'c'fthe ignition contacts'98 and istop the .eng i'n'efon theother hand, if the. shunt field is shortcircuited, the increasedcurrent'iii'th re alator coil 59 will move the regulator core 13 toyalve-closin position,- in which case the fuel supply to t eengiiiewould be'tiu t'dow ii:

and as; a matter of fact the, regulator "coil would robabl hurn'out fso' 'thtitf it would completely de-en'ergized, and'thenthelregulatorcore 13 would close the ignition c'ont ac-ts 98 and stopstheen ins; so. that in anyevent, the engine would initomdfi- '5 withoutThe'undrloadr'elziiy R serves to simplify the construction -'of the ma nswitcli 6 as compared"witl1 the main switlr 6' ofQthe fPardeeapplication 92,421, above mentioned, since it is ordlnarily desirable't'o,h:ii-'e a main switch' closefts main contacts when the flux throughits'core attains a definite.

value, and the closingof the switch should take place at orpracticallynt this prede termincd value ofthe fiux. To d'ri-tlii's, thepull dueto the flux should be balanced fairly accurately against thespringgor other'co'unteracting force, so that aslfght increasein theflu; will i switch; however, if the switch in its' opencircuitingposition, is required to close tightly a set of auxiliary contacts, itisdifficult to secure this nicely-balanced action for accurate closingof the main contacts and at the same time preserve a tight. auxiliarycontact until the moment 'ofiac tually closing the maincontac-ts. Thepresent invention,.by elim nating any auxiliary contacts (in the mainswitch 6, thus simplifies materially the construction of the'sivitch;

device. A

BEST AVAILABLE coex In order to prevent the opening of the dynamotrip-switch 9 whenthe pointer is approaching the contact 71 in acounterclockwise direction, the contact 71 is insu lated on its sidenearest the contact 78 so that the indicator slides by the contact 71Without making electrical contact with it when approaching it in acharging direction (counter-clockwise), but does make electrical contactwhen approaching in a discharging direction (clockwise), that is, whenthe battery is, discharging. a

The description thus far has been directed to a system utilizing a.single engine.

In certain instances, it is more economical to divide the power supplyof the plant among two or more units, and tohave one of these units oflarger capacity than the other; for example,.in.a typicalinstallation alamp load of one ampere or less would be suppliedby the batteryyalone;:the ordinary [ot the respective units. Whenever the 'lainp cu'rrent,drops to aflpredetermined exentxi low therasi inis ta da fi ffe f f eainperes",.th e''coils 5r. the mai'i'i' svYitchQlOG aiiown switch .106toop'en, thereby dis- ;conn' ectingftl e dynamoDD from the load, fandleaving the circuits 'in'the condition in whichfthey were before thelamp load first.v

load of, say, fifteen amperes, would be supplied by a small engine suchas the engine E, driving the double-current dynamo D, l

at approximately its full-load rating; a maximumload, 1 of, say, fiftyamperes, would be-carried by a larger engine EE and dynamo DD, runningeither alone or in parallel with thesmaller: unit E, D. Thi s.,is

conducive to efiiciency of fuel consumption, I

because the units then operateat approximately full load,-whereasaninternal combustion engine running at low loads is relativelyinetficient.

If a second engine EE and single-voltage dynamo DD .are to be added tothe plant above described, the switch 100 in the work circuit. isopened,-and to its terminals are connected the leads 103, 105 tothermain switch 106 and thence to the dynamo DD. A preferred arrangementof parts is indicated in the drawings as comprising shunt and serieswindings 158, 154, the latter connected to the current coil 152 of theenginei'egulator 104E, thence to the dynamo-current coil 148 of the mainswitch 106, to the lead 103 above described. A manual switch 191 isprovided in shunt to the main switch .106; and an underload relay RE isprovided with contacts 146 so designed as to render the engine ignitioninoperative when the dynamo current falls below a predetermined value. Avoltage coil 159 on the regulator solenoid 113 is connected in serieswith the shunt field 158. The lamp current coil 124 of the main switch106 is connected across the leads 103, 105, and carries lamp-currentexcept when the manual short-circuiting switch 191 is closed; thisswitch'191 is used,

however, only when the main switch 106 is out of order. In operation,when the lamp current exceeds fifteen amperes, the lampcurrent coil 124:of the main switch is energized sufficiently to close the switch,whereupon current from the dynamo D flows through the dynaino DD tostart the ,latter and after the engine EE has begun to roand 104C.;L.Th;is adjustment maybe arranged 4 to causethefiinit "EE, DD toassumeall of 77 the load when first cut in and thus cause the ina in switchGto open and shutdown the smaller ,unit D, E until such time as the lampload exceedsjthe-capacityof EE, DD and causes a current greater than oneampere to flo w from' the battery, when the main switch 6 elo ses andstartsthe unit D, 'Eiin the usualfgna'nifier. Or. the regulato'rs 4 and104 may" be ,so adjusted that",when hotly-units arejrunning the divisionof load is at all tim'es fproport onedto the capacities exceeded, the{standard of fitteen amperes; that is, the'sinall cngineEremains'inoperation, driving the small dy a l I10 D to supply the lampsand charge the battery B. It is obvious that the difi'e'rentunits'previoi slyf described need beof unequal .I II'J'Y- Theengiiic Emay be connected to drive, a pump TP, pieterablyfprovided with adiapliragi ii or other typeof valve 99"arranged so that when thepressure on' the valve falls below a predetermined minimum, the valvewill close the contacts 70, causing the voltage coil 43 of the mainswitch 6 to be enere .gized, thereby closing the contactse45', and

energizing the under-load relay- R, which thereupon 'opeiisfthe ignitioncontacts'tti, to start the engine.i idependently of the magnitude of thelamp load or the condition of the battery, thus providing a pressurecontrolled pump-starting apparatus. The pump is preferably provided withsuitable means (not shown such as a by-pass valve, acting as anautomatic unloading device to prevent excessive pressure.

As a modification, in the nature of arefinement and a simplification of.the above system, the main switch 6 may be combined with the trip switch9. v

The undei'load relay R is preterably provided with a retarding devicesuch as a dashpot (Z, to prevent the relay fromclosing the contacts 46during the moment of reversal of dynamo current when: the engine hasbeen started and the dynamo begins to generate.

- ion BEST AVAILABLE COP.

Theutrip switches 9 and 10 may be provided with auxiliary contacts (notshown), arranged to open the circuit of their respective windings, whenthe switches are tripped. These contacts relieve the meter contacts 71and 78 of the duty of breaking an inductive circuit.

In Figure 2 there is illustrated a modified construction differing fromFigure 1 primarily in the relay 7 which in Figure 2 is numbered 207. Inthe modification the relay 207 comprises an operating coil 233 whosecore 234 is mechanically connected to the movable cont-actors 269 and274 adapted to .co-operate respectively with the relatively fixed.contactors 268 and 277. The meter contact 263, which corresponds to asubstantially full-charge condition of the battery is connected by thelead 264 to the righthand movable contactor 274. The startcharge metercontact 230 is connected by the lead 231 to the left-hand fixedcontactor 268: and to the negative side of the relay coil 233,;whose,positive terminal is connected, first, through the lead 241 to thevoltage coil. 243,,of the main-switch 206; second, through the lead 261to the right-hand fixed contactor 277 of the relay 207; and third,to-one of the pump-controlled contacts 270, the other of these contactsbeing grounded.

Ihe,.. operation of the modification illustrated in- Figure 2 followsthe description above given for Figure 1, save for certain differenceswhich may be briefly enumerated. Assume that the voltage coil 243 isdeenergi'zed and that the contacts 245 of the main switch 206 are open.It now a lamploadof say less than one ampere is turned on, in'lthework-circuit, the battery discharges slowly until the meter pointer 202travelsclockwise to the start-charge contact 230. Current will then flowfrom the positive pole of the battery, through the lead 222, voltagecoil 243, lead 241, relay coil 233, lead 231, start-charge contact 230,meterpointer 202, to ground, and thence (referring now to Figure 1)through the intermediate terminal of the dynamo D,

armature winding 26, negative terminal 27, and lead 28, to the negativepole of the battry. "This energizes both the relay coil 233 and themain-switch voltage-coil 243.

Theenergizing of the relay coil 233 closes first the right-handcontactors 274, 27 7, and later closes the left-hand cont-actors 258,269, No circuit changes are effected at this by the closing of theright-hand contactors 274, 277, because the circuit in which saidcontactors are located is open at the stop-charge meter contact 263. Theclosing of the left-hand relay contactors 268, 269, short-circuits thestart-charge meter contact 230 and electrically locks the relay 207 inits closed position, by connecting the negative terminal of the relaycoil 233 directly to ground. w

The energizing of the main-switch voltage-coil 243 closes themain-switch contacts 245. and serves to start the engine as abovedescribed in connection with Figure 1. T consequent charging of thebattery causes the meter pointer 202 to travel counterclockwise towardthe stop-charge contact 263. As the pointer 202 leaves the startchargecontact 230, there is no arcing. be-' cause this contact has beenshort-circuitcd at 268, 269, as above described.

lVhen the meter pointer 202 reaches the stop-charge contact 263. therelay coil 233 is short-circuited through the lead 261. right-hand relaycontactors 277, 274, lead 264, contact 263, meter pointer 202, toground. The relay 7 on being thus de-energized by the short-circuitingof its operating coil 23?; releases its core 234, which then returns toits initial position through the influence of a spring 2350i gravity,first breaking the left-hand contacts 268, 269, and later breaking theright-hand contacts 274, 277. The latter break opens the circuitincluding the main-switch ;voltage-eoil 243, and thus causes the mainswitch 206'toopen, and shut down the engine, unless thelam currentthrough the -"main-switch currentcoil 224 is suflicient' tohold the mains'witch contacts 245 closed, as previously described in connection withFigure 1.

It will be noted that during the opening of the relay contacts, theinitial=break of the circuit including the main-switch volt age-coil 243occurs at the right-hand relay contacts 274, 277 these contacts may bebridged by a condenser-251, if desired, in order to prevent anyobjectionable -arcing. There is no arcing when the meter pointer 202leaves the cont-acts 230 or 263,- because in neither instance is thereany current flowing through the meter pointer at the time the pointerleaves the contact The relay 207 may be a smalland compactdevice ofsimple construction, and the parts'therefor may be readily obtained onthe market at nominal cost; at no time is there a heavy current passingthrough any portion of the relay mechanism. In case the meter 201 isremoved, as for inspection or repair, the relay 207 may be operatedmanually to start and stop the charging of the battery at the propertimes. In' general, the various parts of the apparatus illustrated inFigure 2'are' assigned reference numerals two hundred higher than thereference numerals for the corresponding parts in Figure 1. Bearing thisin mind, itis believed that the operation ofthe apparatus of Figure2"will be clear from the foregoing, without further elaboration.

From the above, it will be seen that the BEST AVAILABLE cos.

several objects of the invention are achieved, and other advantageousresults attained.

As various changes might be made in the above construction, and as theabove invention might be embodied in dillerentforms, it is intended thatall matter set forth in the above description and in the accompanyingdrawings, shall be interpreted as illustrative and not in a limitingsense.

Having thus revealed my invention, I desire to claim as new and secureby Letters Patent of the United States:

1. An electrical system combining a dynamo adapted to run as a motor tostart an engine and to be run as a generator by the engine, a battery, aswitch connecting the dynamo to the battery, and a current relay in thedynamo circuit adapted to stop the engine when the dynamo current fallsbelow a predetermined value, said relay being provided with a retardingdevice to prevent the operation of the relay at the moment of reversalof dynamo current when the engine has been started and the dynamo beginsto generate.

2. An electrical system combining a bat tery; a dynamo provided withshunt and series field windings; an engine coupled to the dynamo; avalve in the fuel supply to the engine; a work circuit; a main switchadapted when closed to connect the dynamo to the battery and workcircuit; a relay adapted'to render inoperative the ignition of theengine to stop the engine when the dynamo current falls below apredetermined value; a meter provided with an indicator for indicatingthe state of charge of the battery; means controlled by the indicatorfor closing the main switch to energize the dynamo to start the enginewhen the battery is suflici'ently discharged, means controlled by theindicator for disconnecting the dynamo from the battery and work circuitand for operating an alarm when the battery is further discharged as byfailure of the dynamo to start the engine, means operated by theindicator for disconnecting the battery from the work circuit when thebattery is still further discharged; a regulator provided with awork-circuit-voltage coil in series with the dynamo shunt field andadapted to move the valve to regulate the fuel supply to the engine tomaintain constant the voltage at the work circuit, and provided with adynamo-current coil opposing the voltage coil to set a differentstandard of voltage at high loads than at low loads; a pump driven bythe engine; and pumppressure-controlled means for closing the mainswitch to start the engine when the pressure of fluid delivered by thepump attains a predetermined value.

3. An electrical system combining a dy-- namo adapted to run as a motorto start an engine and to be run as a generator by the engine, abattery, a relay responsive to dynamo current adapted to stop the enginewhen the dynamo current falls below a predetermined value, said relaybeing provided with a retarding device.

4. An electrical system combining a dynamo adapted to run as a motor tostart an engine and to be runas a generator by the engine, a battery, arelay responsive to dynamo current adapted to stop the engine when thedynamo current falls below a predetermined value, said relay beingprovided with a retarding device, to prevent operation of the relayimmediatelyuponthedropping of said current to zero.

5. An electrical system combining a dynamo adapted to run as a motor tostart an engine and to be run as a generator by the engine, a battery, arelay responsive to dynamo current adapted to stop the engine when thedynamo current falls below a pre determined value, sai'd relay beingprovided with a retarding device, a pump driven by the engine, andpump-pressure-controlled means for starting the engine when the pressureof fluid delivered by the pump attains a predetermined value.

In witness whereof, I hereunto subscribe my name, as attested by the twosubscribing JosEPH BURKE.

